I used to be a blood donor, started out at a smashing 137 but after about five times my haemoglobin was down to like 112. And the leeches at the blood bank didn't say a thing about it! So I quit, and felt much better for it.
What lady said about food is good advice, I firmly believe vitamins and minerals should come from food, not pills.
Also, a friend of mine with similar problems (fatigue, crankiness, stressed out) was adviced by her doctor to take a 30-minute walk every day, because the walking would crush the red bloodcells under her feet, thus stimulating the body to make more... sounds weird, but I guess some time to yourself and a bit of exercise can't hurt.